In application Ser. No. 969,024 filed Dec. 13, 1978 a top operated tank car valve assembly includes a rod extending downwardly from the top of the tank and is attached to a valve stem of a lading valve located in the bottom of the tank. The stem engages a horizontally extending threaded valve sleeve provided with a mounting flange which engages a cooperating mounting flange on a valve cage. Fasteners extend through the valve cage and engage threaded openings in a tank car bottom outlet mounting flange. The cage includes a valve seat for a valve closure movable between opened and closed positions relative to the valve seat. The valve seat is formed on the lower, internal surface of the valve cage, and circumferentially spaced openings are formed in the valve cage for lading flow.
Laterally spaced projections extend upwardly from the lading valve closure. A valve stem retainer includes a pair of formed retainer members which define a cavity or opening. The valve stem retainer engages the lower end of the valve stem with a sufficiently tight fit as to substantially reduce horizontal and angular movement of the stem relative to the stem retainer. Machined surfaces formed in the retainer members receive the projections from the lading valve closure and fasteners hold the formed retainer members in abutting relation to the closure projections.
A valve guide depends from the valve closure a sufficiently short distance as to not extend below the tank mounting flange, and thereby a skid is not required in order to comply with AAR and DOT regulations concerning projections extending below the bottom surface of a railway tank car.
However, the valve closure and retainer are formed as separate members, each requiring machining. The machining operation adds significantly to the cost of the retainer assembly.